Print

Email story

Comment

Letter to the editor

Sizing up ants

USF biologist Deby Cassill holds the lowly fire ant in high esteem, saying the insect can teach us lessons ranging from global cooperation to corporate success.

By SUSAN ASCHOFF
Published November 6, 2004

[Times photos: Cherie Diez]

Biologist Deby Cassill, center, and student researchers Mandy Boesger, left, and Tiffany Nelson examine a mound. The sandy circle is a nest of harvester ants, seed foragers whose queen is hidden 6 to 9 feet below ground.

	An ant colony in Deby Cassill’s USF lab contains a burial mound.

Students swarm the classroom at the University of South Florida St. Petersburg, searching for a chair, leaving stragglers to stand. They've come to hear a professor explain the "evolution of inequality and love."

Biologist Deby Cassill is going to answer life's questions by talking about fire ants.

Cassill, a petite woman in athletic shoes and faded blue jeans riding unfashionably high, a key ring dangling from a belt loop, bounces across the carpet, her eyes wide, her voice animated with excitement.

In the dirt they trod, hundreds of thousands of fire ants meet, mate, build homes, rear young, battle invaders, fetch food and live and die within the colony, their society. On a big-screen TV, Cassill shows a graphic of grouped stick figures. Many are small. One is large.

The large one is the queen.

The queen gets more food, more protection, more status.

The queen shares with the worker ants, not out of altruism, but because it benefits her.

Each ant works for the survival of the colony. But some will die sooner, others are more vulnerable to predators. They are not equals. Equality, says Cassill, does not serve the colony.

Equality does not serve people, either. In our economic system, prosperity occurs only if there are queens and workers, Cassill suggests.

A young man seated at a table toward the back is eating chicken out of a plastic foam container. The lecture began at 11 a.m. The smell of the meat permeates the room.

Another student suggests equality is fairness. Everyone in this room wants to make a good living when they graduate. They all want their professors' equal attention. They all want to be as well-situated as the queen.

They probably want some chicken, because it is almost noon.

Cassill's voice is still bright, her arms open. But her words are those of an unsentimental scientist.

"Once you've equalized the resources," she says, "you're close to extinction."

On Monday mornings, Cassill (pronounced castle) and two undergraduate students go digging for fire ants. They load plastic buckets, talcum powder and a shovel into a car.

"The best colonies are in Brooksville," says Cassill. "Very large. One shovelful and I get 50,000 ants." Today they drive to Lake Maggiore Park in southern Pinellas, to a strip of sandy soil across from a golf course.

Heads bowed, they search for the telltale mounds: flattened, with multiple entrances. Mandy Boesger is a nursing major. She signed on for independent study with Cassill after an "amazing" biology class. She and Tiffany Nelson, who is also a junior, wear shorts. Their arms are bare.

"You're okay as long as you have shoes on," Nelson says. Fire ants bite en masse if disturbed. If a person is not allergic, "It's no worse than a mosquito bite," says Cassill. Still, her jeans are tucked inside her sweat socks.

"Now this is interesting," Cassill says, excitedly calling the students to where she crouches. A sandy circle about the size of a turkey platter is the entrance to a nest of harvester ants, seed foragers whose queen is about an inch long and hidden 6 to 9 feet below ground.

"This is a gorgeous colony," says the teacher. "If there's an alarm, they'll actually tuck their butts under. Their sword is at the front. These are the ants the Aztec would stake their enemies to, and pour honey on them. It was excruciatingly painful."

She stands, beaming.

"I looove this," she says.

Cassill, 57, has been an assistant professor at USF for three years. It took her four decades to discover that ants had the answers to her questions.

She worked on programs for the mentally ill and managed care until, at 42, she reversed course. She enrolled at Florida State University, earning bachelor's, master's and doctoral degrees in biology, rearing her son and "suffering poverty for eight years."

"I was interested in interactions. But I couldn't do my experiments with people. Rats were, um, smelly.

"When I saw my first ant colony I thought, "Oh my gosh."'

There are as many as 20,000 species of ants, and a division of entomology devoted to their study called myrmecology. Researchers worldwide chart the relationships of queens and suitors, sisters and larvae. They videotape battles to the death. They track how scout ants forage for food. Cassill picked fire ants because they live in warm climates, where she prefers to live, and because there is funding available for research from government agencies seeking to kill them.

Despite the onslaught of poisons, fire ants endure.

"What we're learning is we really need to understand the biology," Cassill says.

She is sampling fire ant nests in Brooksville, Feather Sound and St. Petersburg for aggressive colonies versus cooperative colonies. Both kinds of ants will bite the human who disturbs their nest. The adjectives apply to how they live. Aggressive colonies have one queen. Workers kill other queens. Cooperatives will accept unrelated queens and workers and live with multiple nests.

"Here's the puzzle," Cassill says.

"The cooperative colonies are taking over the territory in Florida. The aggressives should be gaining, since they are superior fighters. I'm trying to tease out the benefits (to the ants) of being cooperative."

During the Lake Maggiore trip they dig up three nests, each about a shovel-blade wide and deep, the dirt and insects plunked into a bucket, then talcum powder swabbed on the sides so the ants cannot get traction and escape.

If the ants, which are overwhelmingly female - males are merely "sperm missiles," Cassill says - live together for improved survival, so more queens can go to other colonies, so fewer colonies go to war, Cassill wants to know why colonies still die.

"It's not pest control, but biocontrol - natural agents," she says of their demise.

She suspects the downside of living closer together is vulnerability to disease.

And she theorizes that as ants go, so goes man.

Human society is expanding. We are becoming a global economy, a big cooperative. Globalization should reduce wars. But there will be new threats, she says.

The ants teach us that diseases will regulate human populations as well.

The packed classroom is becoming increasingly stuffy, but the students stay. Cassill presents another slide where many small stick figures, which appear to be running and resemble some sort of hybrid ant man, surround a much larger ant man.

In the 1970s, the scientific dogma was that a queen does better with more workers, she says. But since the purpose of the queen and her colony is to make more babies - a queen can produce 3-million offspring in her 10-year life span - researchers were surprised to find that whether there were 50,000 workers or 300,000, the number of offspring remained about the same.

"I chewed on this about six months," she tells her audience. The answer, she says, is not numbers, but diversity.

"Assume you are parents and you have $100 to invest in offspring. How will you do that?" she asks the students.

One young woman says she will have 100 children and share the money equally.

A young man says he wants two children, each of whom gets half.

"Some of you would have one offspring," Cassill says. Because the single child does not need to share, he has significant resources to "weather problems." The 100 children will do very well in an environment where there is sufficient food.

But the ants teach us that the better strategy is not equality, but diversity. The 100 could be wiped out by famine. An only child is easy prey. So the queen diversifies: She reproduces both royal, or fertile, children and sterile workers.

"She hedges her bets" against a changing environment, Cassill says, to guarantee survival.

A CEO does the same.

"If you study the economy of America, the vast majority earn less than $100,000. One fraction of 1 percent earn more than $10-million," she says. Our queens are the financial moguls.

The students at the lecture may have hoped Cassill's laws of nature would give them tips on climbing the corporate ladder. Instead, she has told them the CEO and the corporation may need them to stay put.

"There's a tradeoff. Each has to decide how hard he wants to fight for resources or whether it is better to be a worker. For self-preservation," she says, "compete for the middle."

In a plastic bin on the laboratory countertop, hundreds of ants scurry about in their own virtual reality show. Their ceaseless movement, their brief encounters, their hunt for food, is captured on a magnifying camera lens and pictured on a television screen.

They are in the Big Brother House for ants.

The ratings are good. They have a dedicated audience.

"It's what I do. I make ant movies," says Cassill. There are 12 plastic shoe boxes in a closet in her lab, where thousands more fire ants scurry in and out of Petri dish nests or suck up sugar water from cotton balls. They pile dead bodies in designated graveyards.

On a television showing a prerecorded video, Cassill watches an ant limp across sand, magnified into white gravel, its detached limbs on the rocks behind it.

"Ummmm, that was quite a battle," says Cassill. "Poor thing."

But she is not sorry.

Assistants Boesger and Nelson carefully lift ants one at a time with "no-kill" forceps into a small Tupperware container. They are looking for aggressives. Aggressives immediately attack others. Aggressives will lock jaws and not let go until one of the combatants is mortally wounded or starves to death. Cooperatives will let go.

Cassill watches the ants make love and war thousands of times in these artificial nests. She feeds them raw meatballs, earthworms and shrimp. She delicately grasps a strand of hair dipped in modeling paint to mark them for identification.

"They look like Shmoos. They're so cute," she singsongs about the grublike larvae, so tiny they appear as white dots.

But even the larvae work, digesting food brought to them by workers so the other ants can "drink" it. Solids cannot pass through an ant's narrow midsection.

"I'm working on a paper right now about child labor," Cassill says.

A chapter she wrote for an economics book is called, "Mogul Games: In Defense of Inequality As an Evolutionary Strategy to Cope With Multiple Agents of Selection."

"It's a cooperative exchange," Cassill says.

"To ants, it's (for) food. To humans, it's money."

She and business school dean Ronald Hill are writing a paper about how ant communication improves on the corporate model. "An ant colony is a self-organizing system of diverse workers of different abilities. But every worker, at some point, has access to the queen. There's open communication," Cassill says.

Corporations are authoritarian with top-down communication. "Top-down will collapse given enough time," she says, citing Enron's demise. "Ant colonies are so successful because workers bring info to the CEO."

Workers, not queens, are also the ones who innovate. Bill Gates, she says, was once a worker.

"I'm one of the masses. I'll never be a mogul," says the professor. But without the responsibility or risks of the queen, she has the flexibility to do what she loves, she says.

Ants consume her days. They visit her at night.

"My favorite dream is, I've found a huge queen and I have no forceps. I just grab the queen with my hands," she says, demonstrating a stranglehold grip.

As a scientist, she says she shies from emotive words.

In the dream, she is gushingly happy.

- Susan Aschoff can be reached at aschoff@sptimes.com or 727 892-2293.

[Last modified November 5, 2004, 09:52:50]